Add dockerized PXE server

pxe/.gitignore

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+archiso/

pxe/Dockerfile

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+FROM archlinux
+
+# Reference:
+# - https://wiki.archlinux.org/title/Syslinux#PXELINUX
+# - https://wiki.syslinux.org/wiki/index.php?title=PXELINUX
+# - https://wiki.syslinux.org/wiki/index.php?title=PXELINUX-Multi-Arch
+# - https://www.saminiir.com/boot-arch-linux-from-pxe/
+
+RUN pacman -Syu --noconfirm dnsmasq darkhttpd syslinux \
+    && yes | pacman -Scc \
+    && mkdir -p /srv/tftp \
+    && ln -s /usr/lib/syslinux/bios/lpxelinux.0 /srv/tftp/lpxelinux.0 \
+    && ln -s /usr/lib/syslinux/bios/ldlinux.c32 /srv/tftp/ldlinux.c32 \
+    && ln -s /usr/lib/syslinux/efi64/syslinux.efi /srv/tftp/syslinux.efi \
+    && ln -s /usr/lib/syslinux/efi64/ldlinux.e64 /srv/tftp/ldlinux.e64 \
+    && mkdir -p /srv/tftp/pxelinux.cfg \
+    && ln -s /archiso/arch/boot/x86_64/vmlinuz-linux /srv/tftp/vmlinuz-linux \
+    && ln -s /archiso/arch/boot/intel-ucode.img /srv/tftp/intel-ucode.img \
+    && ln -s /archiso/arch/boot/amd-ucode.img /srv/tftp/amd-ucode.img \
+    && ln -s /archiso/arch/boot/x86_64/initramfs-linux.img /srv/tftp/initramfs-linux.img
+
+COPY entrypoint.sh /usr/local/bin/entrypoint.sh
+
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

pxe/README.md

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+# Docker container for PXE booting Arch ISO images
+
+This provides a simple docker container to allow serving an archlinux ISO image
+for booting from the network via PXE.
+
+## Build container image
+
+First of all one needs to build the container image:
+
+```sh
+docker build -t arch-pxe .
+```
+
+## Serve ISO with PXE
+
+Having built the container image, we may now use it to serve the contents of an
+Arch ISO using PXE. Assuming we want to serve the ISO located at
+`./archlinux-x86_64.iso` and a DHCP server is already running at `192.168.1.1`:
+
+1. Mount the ISO on the host:
+
+   ```sh
+   mkdir archiso
+   mount -o loop,ro ./archlinux-x86_64.iso ./archiso
+   ```
+
+1. Run the PXE server:
+
+   ```sh
+   docker run -it --rm --privileged --net host -v $(pwd)/archiso:/archiso:ro arch-pxe --dhcp 192.168.1.1
+   ```

pxe/entrypoint.sh

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+#!/bin/bash
+
+set -o pipefail
+
+# Return the first IPv4 address of the first ethernet interface
+get_ip() {
+	local iface
+    local ip
+
+    iface=$(basename $(ls -d /sys/class/net/enp*)) &&
+        ip=$(ip address show dev ${iface} |
+            awk '$1 == "inet" { split($2, a, "/"); print a[1] }') || return 1
+
+    echo ${ip}
+}
+
+
+HTTP_ADDR=$(get_ip) || echo "Failed to get own IP. Please set it with --http."
+
+USAGE="Usage: ${0} [flags]
+
+flags:
+--dhcp addr     The address of the DHCP server to proxy. Required.
+--http addr     The address of the HTTP server. Default ${HTTP_ADDR}."
+
+usage() {
+    echo "${USAGE}"
+    exit 1
+}
+
+
+while [ ! -z ${1} ]; do
+    case ${1} in
+        --dhcp)
+            shift
+            if [ -z ${1} ]; then
+                usage
+            fi
+            DHCP_ADDR=${1}
+            shift
+            ;;
+        --http)
+            shift
+            if [ -z ${1} ]; then
+                usage
+            fi
+            HTTP_ADDR=${1}
+            shift
+            ;;
+        *)
+            usage
+            ;;
+    esac
+done
+
+if [ -z ${DHCP_ADDR} ] || [ -z ${HTTP_ADDR} ]; then
+    usage
+fi
+
+
+cat > /etc/dnsmasq.conf <<EOF
+# Don't function as dns server
+port=0
+
+# Function as a proxy DHCP
+dhcp-range=${DHCP_ADDR},proxy
+dhcp-no-override
+
+# tftp server setup
+enable-tftp
+tftp-root=/srv/tftp
+
+# Log extra information about dhcp transactions (for debug purposes)
+log-dhcp
+
+# NOTE: For some reason, dhcp-boot doesn't seem to work.
+pxe-service=x86PC,"PXELINUX (BIOS)",/lpxelinux
+pxe-service=X86-64_EFI,"PXELINUX (EFI)",/syslinux.efi
+EOF
+
+cat > /srv/tftp/pxelinux.cfg/default <<EOF
+DEFAULT archlinux
+
+LABEL archlinux
+    MENU LABEL Arch Linux x86_64 PXE
+    LINUX /vmlinuz-linux
+    INITRD /intel-ucode.img,/amd-ucode.img,/initramfs-linux.img
+    APPEND archiso_http_srv=http://${HTTP_ADDR}/
+    SYSAPPEND 3
+EOF
+
+# NOTE: dnsmasq launches in the background by default
+dnsmasq
+
+darkhttpd /archiso